Method of recovering cumene

ABSTRACT

A process for recovering cumene, characterized by subjecting 2,3-dimethyl-2,3-diphenylbutane produced in a process in which cumene is used, to hydrogenolysis in the presence of a catalyst thereby to convert it into cumene, and recovering the cumene.

TECHNICAL FIELD

[0001] The present invention relates to a process for recovering cumene.More particularly, the present invention relates to a process forrecovering cumene, in which 2,3-dimethyl-2,3-diphenylbutane produced ina process in which cumene is used, is efficiently recovered as cumene.

BACKGROUND ART

[0002] As a process using cumene as a raw material for reaction, thereare known a process having steps of converting cumene into cumenehydroperoxide and obtaining propylene oxide from such cumenehydroperoxide and propylene, aprocess of converting cumene into cumenehydroperoxide and obtaining phenol and acetone by subjecting such cumenehydroperoxide to acidolysis, and the like. In those processes, there isa reaction producing 2,3-dimethyl-2,3-diphenylbutane by dimerizingcumene as an undesirable side-reaction. By-production of2,3-dimethyl-2,3-diphenylbutane causes undesirable effects such asconsumption of cumene and obstruction to a desired reaction.

DISCLOSURE OF THE INVENTION

[0003] An object of the present invention is to provide a process forrecovering cumene, in which 2,3-dimethyl-2,3-diphenylbutane produced ina process in which cumene is used, is efficiently recovered as cumene.

[0004] Namely, the present invention relates to a process for recoveringcumene, which comprises:

[0005] subjecting 2,3-dimethyl-2,3-diphenylbutane produced in a processin which cumene is used, to hydrogenolysis in the presence of a catalystthereby to it convert into cumene, and recovering cumene.

BEST MODE FOR CARRYING OUT THE INVENTION

[0006] As a process using cumene, there can be listed a process havingsteps of converting cumene into cumene hydroperoxide and obtainingpropylene oxide from such cumene hydroperoxide and propylene, a processof converting cumene into cumene hydroperoxide and obtaining phenol andacetone by subjecting such cumene hydroperoxide to acidolysis, and thelike.

[0007] The recovering process of the present invention is to recovercumene obtained by subjecting 2,3-dimethyl-2,3-diphenylbutane producedto hydrogenolysis in the presence of a catalyst thereby to convert itinto cumene.

[0008] As the catalyst, a catalyst containing a metal of Group 10 or 11of the Periodic Table (IUPAC Inorganic chemistry nomenclature, revisededition(1989)), is preferable. The metal is preferably at least oneselected from the group consisting of copper, palladium, platinum andnickel. It is preferable to use a copper-based catalyst from theviewpoint of suppressing of by-products. As the copper-based catalyst,there can be listed copper, Raney copper, copper-chromium, copper-zinc,copper-chromium-zinc, copper-silica, copper-alumina, etc.

[0009] Hydrogenolysis can be carried out in a liquid phase or gas phase.A hydrogenolysis temperature is usually 0 to 500° C., and preferably 30to 400° C. It is advantageous that a pressure is usually 100 to 10000kPa. It is good that hydrogen exists equi-molar to2,3-dimethyl-2,3-diphenylbutane or more. Hydrogenolysis can beadvantageously carried out using a catalyst having a shape suitable fora slurry or fixed bed.

[0010] The process of the present invention can be conducted in batch,semi-continuous or continuous process.

[0011] When the process using cumene is a process having a step ofobtaining propylene oxide from cumene hydroperoxide and propylene, it ispreferable that hydrogenolysis is carried out after propylene oxide isseparated and removed from the reaction products. When it is required torecover cumene from cumyl alcohol, hydrogenolysis can be also subjectedto a reaction liquid containing cumyl alcohol as it is because cumylalcohol produced in the step of obtaining propylene oxide from cumenehydroperoxide and propylene, is converted into cumene by hydrogenolysis,and when it is not desired to subject cumyl alcohol to hydrolysis,hydrolysis can be carried out after separating and removing cumylalcohol. Hydrolysis can be carried out after separating and removingcumyl alcohol. It is preferable to carry out hydrolysis afterseparating-removing or concentrating 2,3-dimethyl-2,3-diphenylbutanefrom a view point of suppressing side-reactions of effective ingredientssuch cumene, cumyl alcohol and the like to a minimum.

[0012] When the process in which cumene is used, is a process forobtaining phenol and acetone by subjecting cumene hydroperoxide toacidolysis, it is preferable to carry out hydrolysis after separatingand removing acetone and phenol to minimize losses caused tohydrogenation of acetone and nuclear-hydrogenation of phenol.

[0013] Cumene recovered can be used effectively in the same process oranother process.

EXAMPLE Example 1

[0014] A solution containing 1% by weight of2,3-dimethyl-2,3-diphenylbutane was passed through a reactor filled with16 cc of a copper-chromium catalyst (3 mm ø pellet) at a rate of 1g/minute at a temperature of 220 to 260° C. under a pressure of 1 MPaGtogether with 300 cc/minute of hydrogen. Results were shown in Table 1.TABLE 1 2,3-Dimethyl-2,3- Cumene Reaction diphenylbutane selectivitytemperature conversion *1 *2 220° C. 84% 100% 240° C. 97% 100% 260° C.100% 100%

Industrial Applicability

[0015] As described above, according to the present invention, a processfor recovering cumene, in which 2,3-dimethyl-2,3-diphenylbutane producedin a process in which cumene is used, is efficiently recovered ascumene, can be provided.

1. A process for recovering cumene, which comprises: subjecting2,3-dimethyl-2,3-diphenylbutane produced in a process in which cumene isused, to hydrogenolysis in the presence of a catalyst thereby to convertit into cumene, and recovering the cumene.
 2. The process for recoveringcumene according to claim 1, wherein the catalyst is a catalystcontaining a metal of Group 10 or 11 of the periodic table.
 3. Theprocess for recovering cumene according to claim 1, the metal is atleast one selected from the group consisting of copper, palladium,platinum and nickel.
 4. The process for recovering cumene according toclaim 1, wherein the process in which cumene is used, contains steps ofconverting cumene into cumene hydroperoxide and obtaining propyleneoxide from the cumene hydroperoxide and propylene.